Aerial system for wireless signaling



Aug. 30, 1932. T. L. ECKERSLEY 1,874,941

AERIAL SYSTEM FOR WIRELESS SIGNALING Filed Nov 1-5, 1928 L mmmar1mmmm1mm,

avwentoz THOMAS L. ECKERSLE'Y 35 HTS Patented Aug. 30, 1932' UNITED *srA PATENT OFFICE- THOMAS LYDWELL ECKIlRSLEY, OE DANBURY, ENGLAND, ASSIGNOR TO RADIO CORPORATION OF AMERICA, A CORPORATION OF DELAWARE AERIAL. SYSTEM FOR WIRELESS SIGNALING Application filed November 15, 1928, Serial No. 319,70' 7, and in Great Britain November 18, 1927. 5

This invention relates to aerial systems for wireless signaling, and has for its principal object to provide an aerial system which, while simple and cheap to construct, shall'be 5 capable of more eflicient radiation or reception.

WVhen a plurality, say, two, similar aerials are coupled to a single load and are sufficient- 1y separated as substantially not to interfere with one another, each aerial will receive a definite amount of energy, one half of which is supplied to the load. If, therefore, the two aerials are properly coupled to the load, the energy which will be received from the two aerials is twice that which would be received upon a single aerial.

It has been generally assumed that there is a definite amount of energy which each aerial can draw from the ether and that each can only draw this amount when it is completely separated from the other, so that the maximum amount of energy which is commonly believed to be obtainable from two aerials is twice that obtainable from one.

I have found, however, that bycorrectly separating a pair of aerials and arranging them so that the E. M. F. therein is in phase, it is possible to cause each aerialto assist the other in drawing from the ether more energy than it could draw alone, and that a similar advantage can be obtained when the aerials are employed to transmit.

If two aerials receive a current I and the E. M. F. in each is E, then, if the E. M. F. is in phase with the current, the gross energy in the pair of aerials is 2E1. Using the customary symbols of R for the radiation resistance of the two aerials e, of the system) and R for the effective resistance of the load, the energy received by the load will be (2XI) R and the energy re-radiated (2 X I) 3. Obviously, equilibrium is reached when 2E1 (R+R (2XI) i. e. when and since maximum energy is supplied to the load when R =B, for the condition of maximum supplyto the load Hence, it follows that the maximu1 n amount of energy will be supplied to the load when the radiation resistance of the system is reduced to a minimum. The radiation re-- sistance of the system is a function of the separation of the aerials, and the value 0 (where R is the radiation resistance of a single aerial) has a fairly well marked minimum when the separation of theaerials is .57 of the wave length, at which separation the ratiofg wpproximately) .3.v Thus, if

a pair of aerials be'separated by .57 of the wave length, the energy which is usefully radiation resistance calculated from the radiation resistance of the separate aerials considered as in parallel;

j, Preferably the separation of adjacent aerials is approximately .57 of the, wave length, and should not exceed .75 of the wave length or be less than .43 of the wavelength.

-. Marked advantages are obtained when the separation lies between .5 and .68 of the wave length. a

Q 'When; the aerials are employed for "transmission, the single'circuit' coupled thereto is,

of course, constituted by a transmitter, 'while when the aerials are employed for reception,

the said circuit is constituted by a receiving circuit and the aerials are energized in phase by being erected in a line at right angles to the direction of the incoming signals.

In one way of carrying out the i1ivention,-a pair of vertical aerials, each containing a V series tuning condenser is erected at a'sepa-' ration of .57 of the wave lengthand the energy from each of the said aerials is supplied via a tapped aerial transformer and a feeder to a pair oftappings upon an inductance coil forming part ofa tuned, cirp cuit. The two tuned circuits are coupled to asingle coil associated with an amplifier and receiver.

The nvention is lllustrated 1n the accompanyingdrawing, which shows schematically one arrangement in accordance therewith.

Referrlng to the drawlng, A-B are two similar aerials of any known kind, for example, they may be ordinary open aerials or they may be vertical aerials whose length is a multiple of a half wave length, and in which the radiation from alternate half wave lengths is annulled or reduced. The aerials A B are separated by a distance of from .48 to .75 of a wave length, but preferably by a distance equal to .57 of a wave length, and are connected at tapping points T1, T and T2, T, to a pair of parallel connected feeders actual radiation resistance of the system as a whole is less than the radiation resistance of the separate aerials considered in parallel.

2. An aerial system comprising a plurality of aerials coupled to a single circuit and formers together, the feeders being tapped to points on the transformerv such that the portion of the transformer included between the feeder tapping points equals, for eachradiator, the surge impedance of the corresponding radiator, a transformer connected across said feeders, and, a transmissionline tapped to said last mentioned transformer. THOMAS LYDWELL EGKERSLEY.

P, Q, which are in turn coupled through a c I o 2 to 1 ratio transformer T3 to a main feeder F, leading to a transmitter or receiver as the case may be. The tappings T1, T T2, T should be such that the impedance T1, T equals the surge impedance of the aerial A,

while the impedance T2, T equals that of the I aerial B.

It is found that with the arrangement above described maximum radiation or signal strength is obtained in or from a direction substantially at right angles to the line A B, while it will be seen that the installation is very simple and cheap. I

No claim is made in this specification to 'so-called beam aerial s stems com risin D a plurality .of a-erials energized in phase and spaced apart by approximately not more than one half wave length, so as to constitutesheet aerials. The present invention may be regarded as providing an aerial systemv giving results comparable to those obtainable from beam aerials but of greater simplicity and less cost.

Having now particularly described and Y ascertainedthe nature of my said invention and inwhat manner the same is to be per- 1 formed, I declare that what I claim'is:-

1. An aerial system comprising a plurality of aerials coupled to a single circuit and adapted to be energized in phase, the separation of said'aerials being more than .5 and less than .68 of a wave length whereby the 

